Systems and methods for making gypsum board using a liquid gypsum set accelerator. Stucco and water are mixed to form a gypsum slurry, such as in a pin mixer. A gypsum set accelerator is mixed with a liquid medium to form a liquid gypsum set accelerator, such as in an eductor. The liquid gypsum set accelerator is added to the gypsum slurry, which is shaped to form the gypsum board.

A method and device for producing lightweight panels with a core of gypsum or of cement and gypsum, with pores for decreasing volumetric weight, and with a covering made of cardboard or of a sheet of glass fibers. The production line does not change except for the addition of a device which forms closed hollow cavities within a suspension in an area where an upper sheet covers the suspension. Air pressure which is fed into the formed cavities is slightly higher than the hydraulic pressure of the suspension, so as to prevent the gaps being filled by the suspension. The layers are less thick, and the type and dimensions of the cavities and the thickness of the walls are varied depending on the desired qualities of the panels.

A composition for forming moulded mantels, columns and other decorative enhancement to fireplace openings is formed of a mixture of alpha hemihydrate gypsum plaster, cement, filler and milled fiber. By using this composition with water and acrylic binder a mixture is formed which sets and gains strength quickly and is an ideal material for manufacturing architectural and decorative structures. Advantageously, a casted piece can be removed from a mould within two to three hours after casting. The finished product has a desired finish that is similar to a casted gypsum cement, referred to sometimes as a honed finish which can withstand high heat, discoloration and cracking while maintaining suitable strength when exposed to typical temperatures of a fireplace surround in indoor applications.

A pretreatment mixing and stirring device, arranged at a stage prior to a slurry formation mixing and stirring device which forms a gypsum slurry by kneading a calcined gypsum and water, and performing a pretreatment by mixing a calcined gypsum with one or more kinds of additives selected from liquids and powders, comprising: a cylindrical housing having a top plate, a bottom plate arranged to oppose to the top plate, a side plate arranged between the top plate and the bottom plate, and a mixing and stirring region where the calcined gypsum and the additive are mixed and stirred in an interior surrounded by the top plate, the bottom plate, and the side plate; a disk-shaped rotating plate arranged inside the housing; a rotating drive shaft, penetrating the top plate or the bottom plate of the housing, and coupled to the rotating plate; a calcined gypsum supply port, arranged in the top plate, and configured to supply the calcined gypsum to the mixing and stirring region; and an additive supply port, arranged in one of or both of the top plate and the side plate, and configured to supply the additive to the mixing and stirring region, is provided.

An apparatus for inserting and removing a mixer rotor pin includes at least one rotor pin with a transverse bore, as well as a rod dimensioned for slidably engaging the transverse bore. The apparatus also includes a mixer rotor pin insertion and removal tool having a tool body. A bottom of the tool has a slot for selectively engaging the aforementioned rod upon insertion of the rod into the transverse bore, and a top of the tool has a non-circular socket for accommodating a driver tool.

An agitator for a gypsum wallboard mixer is provided and includes a circular disc with an upper surface, a drive shaft extending vertically from the upper surface, a lump ring secured to the upper surface, the lump ring being provided in a plurality of spaced, adjacent arcuate segments.

A method for production of a gypsum fiberboard panel, has the following method steps: production of a mixture of calcined gypsum and fibers; application of the mixture to a gas-permeable and/or air-permeable and/or liquid-permeable conveyor that continuously moves in an advancing direction, at an advancing speed; pre-compaction of the mixture; wetting of the mixture with setting water; post-compaction of the mixture; pressing the mixture to form a gypsum fiberboard panel strand; cutting the gypsum fiberboard panel strand into individual gypsum fiberboard panels; drying the gypsum fiberboard panels; and if necessary, finishing and/or coating the dried gypsum fiberboard panels; wherein for pre-compaction, the mixture is sprayed with a water mist and has a partial vacuum applied to it. Furthermore, an apparatus produces a gypsum fiberboard panel, in particular by carrying out the method, and a gypsum fiberboard panel is produced using the method and/or using the apparatus.

A method for continuously forming gypsum-based panels of high fixing strength comprises the steps of: •forming a mixture comprising stucco, non-pregelatinized migratory starch, glass fibre, fluidizer and water; •casting the mixture in a continuous band; •maintaining the band under conditions sufficient for the stucco to form an interlocking matrix of set gypsum; •cutting the band to form one or more wet panel precursors; and •drying the wet panel precursor to form one or more gypsum-based panels. •The weight ratio of water to stucco in the mixture is less than 0.7; •the stucco is present in the mixture in an amount of over 60 wt % relative to the total solids content of the mixture; •the starch is present in the mixture in an amount of over 3 wt % relative to the stucco; •the glass fibre is present in the mixture in an amount of over 1 wt % relative to the stucco; •the fluidizer is present in the mixture in an amount of at least 0.1 wt % relative to the stucco; and the density of the gypsum-based panel is greater than 700 kg/m.

A method and device for modifying a building panel. The building panel including a first surface comprising a facing paper and a second surface comprising a backing paper with a core of calcium sulfate hemihydrate arranged between the facing paper and the backing paper. The method including applying a solution to a predetermined portion of the facing paper, the backing paper, or the facing and backing paper to sufficiently hydrate at least a predetermined portion of the hemihydrate core to convert it to deformable calcium sulfate dihydrate. The solution including at least one alcohol and water. A predetermined force is applied to the deformable portion of the building panel. The predetermined force causing a desired deformation of the predetermined hydrated portion of the building panel. The device for modifying a building panel according to the method includes a building panel mounting structure, a liquid applicator, and a force applicator.

A gypsum slurry mixer output canister is provided, including a canister housing having an upper end, an opposite lower end and defining a canister interior, a cover secured to the upper end, a slurry inlet in operational relationship to the upper end, a spiral block associated with the upper end, and having a helical flow surface depending into the interior. A flow distributor is secured to the lower end and is in fluid communication with the interior, and a slurry outlet is defined by the lower canister housing end.